Dental chair



June 1 1926,

G. D. HECK DENTAL. CHAIR Init N N@ MN wmv @NN June 1 1926.

June 1 1926.

G. D. HECK DENTAL CHAIR Filed April 18. 1922 6 Sheets-Sheet 3 Y@ @Naw 3mm/whole Gecrgehfeck,

HECK

DENTAL CHAIR June 1 1926.

Filed April 18, 1922 6 SheetS-Sheet 4 IWJ @NBN Fete-interi Jane l, 1926a 'if-s.

te A.

D. HECK, PRNCE BAY, NEW YORK, ASSIGNOR T0 THE S. S. WHITE DENTAL DENTAL CHAR.

The principal objects ofmy invention are.

to provide a dental chair with a 'toot-rest that 'may normally assume a position closely approaching the floor, and that may he adjusted'to closely approach the chair seat and be retainedin any position intermediate of its range ot'movement.

Other ebieete eff my'lavelltell efe te rre* vide novel Vn ieans' to so yieldingly support the toe-board in inclined relation to the tooltlooard that it will 'yield to any abnormal pressure lexertedby the patient in the chair, te assume a peeten substantiel? @lined with the foot-hoard or 'platform whereby possible injury to the patient or chair may be avoided- Farther objects of my invention are to provide compensating means arranged to he conveniently aetueteel bi the feet' ef the operator-fte etiect the ladjnstment of the toothoard toward and from the chair seat with minimum effort;V and to automac ticallyl retain said oot--looard'in' any adjusted position within itsv range' of movement, `when released bythe operator. f

My invention valso comprehends a footleS hdoVlg' ils QbQlld 'flame Ylllvofed t0 the footboard rame'so as to swing, from its normaly Qntwardly inclined position, toward the chair seat and he retained inwardlyV inelnedfand ,means eeeveeeltlr eetueted by theptoot of the operator to Aetteet its lrelease and movement- The form ot my invention as .hereinafter describedcomprises 'an Yoperating chair -provided vwithVaf"feet-rest hailing a foot-board 'trarne pivotedto the` chair trameyt'o swing Atoward and from the chair seat', and heinaintained ina substantially hoiiontal position; a toe-hoard @frame pivoted tothe {cotto-ard frame, and arranged to swing independently thereoftoward and from the chairseat 'and to be yieldingly `held in its normallyinclined position intermediate of its range of movement by a spring actuated plunger rod, anda foot-board actuating kvpedal "connected by compensating lvlever and link "mechanism.l with means arranged to eiectfthe actuation of the toot-board, and"toautoinatically retainsaid' foot-'board 'in its adjusted 'position and release it when desired.' `l

flnthe'accompanying drawings, Figure l is a plan view,` 'partiallyin "Section5 of a foot-rest constructed in" accordance 'with my invention`,"tlie tootlooard a'nd'to'e-hoard being removed for conveniencev of illustration; F 2 -is'a'central verticallongitudinal'sectional view otfsaid 'foot-rest showing cerL tain'ot the parts in elevation for conve'nl ience of illustrationand' showing the yparte extended to their full' limit and'in their lowermost position to'clo'sely approach the ti'or; Fig. A3 isa central'. verticall 'sectional view of saidtoot-rest,similar to Fig'. 2,'but showing 'the toe-board `:trame in` itsnormal'ly inclined positiongFig. disa sectional' 'elevational" view of said toot-rest'lv showing' the tootboard' frame' 'raised with respect to the chair seat to accommodate the patient of relatively smaller "stature than 'would he comfortably accommodated by the" foot-rest in the 'position' shown in'Fig."3;'Fig1 5 isti sectional elevationalview showing the lfootrest fra-me' further elevated with respect Vto the chair seaty and in positionto accommodate aI child patientoin the chair; Fig. 6 is a! side elevational view of a dental vchair having'the' foot-rest shown'partially' in' longitudinal section and partially inv elevation, with the toe-board'ifra'1ne`olded back so as to occupy the smallest possible space and in a position to aiiord a stipp jrt"for the feet of a very small child; 7' is 4a rear elevational view showing the compensating and lockingmechanism'as vshown in 3; Fig. 8 is an enlarged detailed'view showing the locking har; Fig. gis', a transverse'sectional view taken on the line 9 9 in 8, sho'wing said locking harV in its 'released position; Fig. l0 is a transverse sectional view similar to Fig. 9, loutshowing'theA locking bar in its lockedposition, Eand Fig. ll is a side elevational view of a modification of the foot-rest actuating and locking mechanism.

ln said igures the chair comprises-the base frame l, seat trame 2 carrying the seat 3. and has the usual depending frame bracket arms el, which are connected forwardl)v b v the transverse bar 5, and which carry the foot-board or plat-forni frame G, having the foot-board 'T supported thereon. The platform or foot-board frame G is provided near its forward end with bearings 8 'tor the shalt t) upon which the toe-board frame l0, having the lateral rearwardly extending arms ll, is mounted tor oscillation, one otsaid arms ll being extended bevond the shaft 9 to provide the lever 1Q, as shown in l, 3, Al and 5.

The toe-board frame l carries the toeboard 13, is provided at its outer end with the usual foot-rest bar li and has the rearwardl)v extending centralljvv disposed lever arms l normallyv projecting beneath the foot-board 7. The lever arms l2 and 15 terminate in bearings 1T and 1S respectively, in which the rock-shaft 19 carrying the slidebracket 2O and controlling pedal 22 secured thereto, is mounted.

The slide-bracket 2O is mounted to slide upon the longitudinally extended slide-rod QS. and normall)7 rests against the butter spri e interposed between it and the collar o secured on said slide-rod 23. The slide-braclnet 2O is capable oi sliding torwardlj.' on the slide-rod 23 to canse the toe-- board 'trame to assume its folded back positionr` as shown in F ig. (l, wherein said slidebracket 2O ma)7 engage the notch 27 at the tree end ot said slide-rod Q3, to retain said toe-board frame l() in such folded back p0- sition.

As best shown in said Fig. 6, the slidebracket 20 is provided with a 'forwardly projecting lue QS arranged to engage the flataprinp; 29 at the forw ard end of the slide-rod 23. which not only forms a buffer for said slide-bracket Q0, but also holds it in the notch 27 and tends to start it rearwardly, when it is released from the notch Qi' b v a slight anti-clockwise twist of the pedal 22, conveniently effected bv the toot of the operator, who, by further moving` his foot backward in engagement with said iedal 22, may cause the toe-board frame l0 to assume its normal position shown in Figs. 3. l and The slide-rod Q3 is arranged to slide longitudinally in the pivoted slide-bearing;` 30, inonnted for oscillation on the pintle 3l. which .is carried b v the lugs 32 extending vtorwardlj.' from the rearward transverse bar 33 of the foot-rest frame 6. The slide-rod Q3 is provided at its rear end with the e llar between which and the pivoted slide-bearing 30, is disposed the spiral butler spring 36. arranged to engage said slide-bearing` SO when said slide-rod Q3 is drawn forward to its normal position. as shown in Figs. fh i and (S.

The slide-rod Q3 is also provided with the voke 3T secured thereto and having itsv laterallv extended wings 3f) connected with suitable lugs -ltl depending from the 'forward transverse bar All of the foot-board 'frame t3. by springs tending to shift the slide-rod 23 longitudinallj,vv t'orward with the butler spring 3G ei aging the slide-bearing 30.

rThe ...-iest liame t3 is supported tor relative movement with respect to the chair seat, and iconnected with the depeinling` traine bracket arms i bj; the levers l-l which are pivoted intermediate ot their ends to said l'ramc bracket arms l and arranged to oseillate on the shalt l5, to which thejv are rigidl;v secured. Said 'loot-rest traine t3 has the bearings -l 'lor the shalt iT which is pielerablj,v pinned or otherwise rigidliv sccnred to the for ard l'rce ends of .v-aid leven-i 43, so that when they are rocked upon the sha tit lo. the finit-rest 'trame will be raised or lowered in a movement about the axis olf said shatt.

As shown in Figs. 2, 3, l, :7, and t3 ot thf` drawings`r the Vtoot-board maintained in a definite s '(tlit'llv inclined angular relation to 'he hoor.. r dless ot its elevated positionby the link traine comprising the lateral links rigidi)v joined b v the transverse connecting bars 4:9 and 5t). The links #1S connect the shaft l which is mounted in the hearing lugs depending 'from the side bars of the foot-rest frame 6, with the sha tt 53, which is mounted in the tree lower extremities ol: the depending traine bracket arms d.

It will be obvious that', as the artes ot the shatts 7, 5l and 53 pass through thev 'tour corners of a parallelo rain, anjv inovement o't the rA ovable sha'lts L7 and 5l about the axes of the shafts and 53 will be in a definite relation, and consequently the angle of inclination of the toot-board will be invariable.

The actuation of the toot-resti is conveg'iiently effected by a toot pedil connected therewith b v a series of compensating and compounding links and levers7 the toot-rest supporting levers -lS being extended rearwardly and provided with trunnions :35, upon which is pivotcd the locking bar 5o, arranged to oscillate thereon to ell'ect tl locking and release et the foot-rest, in itsl different adjusted positions as will be hereinafter described.

The locking,r bar 5G is provided with the bearing lugs 57 carrying the shaft 59, which is connected by the link GO with the lever (Si, having the lateral bearings G3 mounted on the shaft Gl which is carried by the lugs o5 and G6 projecting inwardly from the transverse bar 5 of the chair frame.

The lever Gl carries the toot pedal CT. which is pivoted thereto at its free end. on the shaft GS and which is connected b v the link 69 with the rocking vokc TO mounted llt) to 'rock' con" .the 'shaft' 7i, 'to which'v one end lu'g'ifi projectingrom 'the locking'ba-r 56,

so that a 'downward movementV of the rear end of: the r-toot pedal '67' roc-lied on the-shaft @f8-'tends to Arock'the'yoke F0 -andconnected locking bar ,56 on their respectiveanfesoft .osciliat-ron', which eiiectsthe 'releasevv oi the lock Which holds the toot-'rest in any raised position.

The locking '56 VCarr-ies Aat its center the locking' 'lug T5- Wlri'oh iis provided with the" aperturev 76 therein, having the tor-Ward por-l tion vo'f'its upper Wall `slightly extended to provideagripping'pa'd 78 and arranged'to embrac'evthe upper' surface ofthe "lockingv rodf`79, asbest :shown in Figs. 8, 9 and i0. Disposed Within the-aperture 76 land-opposed tothe gripping'pad 78 is loosely mounted' the 'shoe' '80,' having kthevsenii-cylindrical sur'- face; which substantial-'ly conforms to the' lower surface` of the lock-'ing rod 79, being held in cooperative engagement therewithby' the-threaded adj usting stud 82 in thread ed` engagement with the- -loc'king ba-r 56 and having the' end oi its shank rounded andE entered intoe `semispherical 'socket' 831m the shoeSO, to' form a pivot therefor so that said' shoe may be free to lrock upon saidl rounded endv ofthe' shank' and .thereby accommodate its ricevernent tolbear uniformly on the locke ingfgrod 79"in any angular'position which said! -rodma-y' assume on its supporting 'pintle- '84 inthe` bracket 85' depending 'tromthe cliairffi'am'e, to which said bracket Ai'srigidly secured, as best show-n 4in Figs. 4i, 5 and "7'.

The'locking'iu-g 75 carriesthe leaf-'spring SG'YWfliieh bea-rs against the top' surface' of the`loelin'geroclJ '79 'and 'tends' toA rock the lockingeba'r '56 into` its locked position, as sl-iown in Fig. 10;l Sufperimposed"upon said spring "86 vis the yguard plate S7, which is -en gafged Witllrsaidf" lug'T, toili'old the :spr-'ing- 86 'in position, Vby' the screw 89. The 'guardi' plate '87,' 4as ebestfsliowfn iin Fig. 9', isf arranged to limit the)A rocking' movemento-f'the `locking'vfbar 56f-wl1en-actuatedlby jthe pedal 67' to release-thefloe'kingr lug` from the lockingV 'rodI 79'1avh'en it is-desirecllto lower the toot-rest :trom a'djaisted position. Asbest sho-ivn inf Figs'. 9` andr 150', the adjusted stud 82' lis arrange'dto be held 'inv-its adjusted position by the-setscrew- 8i.

The movement of the foot-'rest is limited bythe cushioning springs 90, which aire disposedf insuifjab'ly formedy lsockets vor 'recesses 91 in thef'l'inks, andso yproject'therefrom as to engagefthe vbuli'er pads' 92,011 the foot rest trame when .in its lowered position, as show-n 'inA Fig.' l', anda arrangedto abut against 'the -buier pads 93, provided von the transverse 'rameba'r 5', when said' footerest isra-isedf .tol its-uppermost position, as show-n in' Fig: 5'.

Et 'W-ill beaobserved that when the toot-rest' is raised' to thewufpper :limit-of its movement',

asshownin Fig. 5, 'it wifll'fhave passedwhat maybe' termed i'tsdea'd center7 ;v thatV is' to say, the axes oithe shafts if? and 51 Wil-l; be disposed behind the vertical plane of theshaftts t5 and1 58,'a1nd-theretore its initial movement th'eretrom must be `eilgected'fby an agentzother than gravity. llo e'iiect the initial lmo-vement .ot the 'toot-rest' from its uppermost position, shown in Figi". the links i8 are presided. with fiat leaf springs 95,

which are provided to bear against' the` transverse `frame bar 5 under such iiex'ed tension 'that when `the locking mechanism isreleased, said` springs Will be efli'eotive to torce the toot-rest forward to a position Wherel its `iur-ther movementv will be eectedz by gravity.

In the form of mv invention, shown in Fig. lil, the toot-restw'frame96 is carried 'by the links 9"?, which are pivoted upon: thedepending trame bracket arms 98, said levers 97 :being arranged to be actuated to raise and lower the foot-rest frame 96 by t-he toot pedal 99", which is mounted on 'the locking bar 100, pivoted to rock on. the 101 and having the locking' lug fIOQjcooperative with the locking bar 103. In this yform o'f my invention the compensating and compounding links and levers are eliminated, the foot pedal and' locking bar, being'idirectly vconnected Ato `the levers-97, Will. necessitateg'reater'application of power and aise must very closely approach the i'oor and, therefore, this form does not possess the ad:- vafnta'ges of the compounding' and compenf sating' mechanism shown in Figs.v l to l() inclusive.

It will be obvious that While a foot-rest, 1'

the foot-rest and its operating pedal said l foot-rest may be adjusted withV but little power and' may ver-y closely approach the iioor, While the operating pedal may have ampie room to` function Without inconvenience "to the` operator.

do `not :desire to-limit my. invention to `the precise details of construction' and varrangement as herein specified, as 'it is .ohvaon's that various modifications may 'bo f: made'therem without departing iromthees- 1 sentiall features oft my invention as deiined intheappended claims.

Having' thus described my invention', I cla-im l. 'In a dental chair, the combination with ico Cil

a seat supportingT iframe, of a `toot-rest trame pirotally supported thereon and arranged to be adjusted toward and from the chair seat. a toe-board trame pivoted to said toot-rest' trarne 1 arranged to be inclined either toward or Lrom sai(l seat, a slide-rod carried b3' said toot-rest trame, and means on said toe-board trame cooperative with said slide-rod to retain the toe-board :trame incl'ned toward the chair seat or yieldingly rctrined inclined :may 'from said seat.

L. tu a dental chair. the combination with a seat .supporting` traine ot a toot-rest frame piroted to sn'inn' ffurard and from the chair seat, a toe-board me niroted on said tootboard Vtrame to swing toward and from said seat iudenemlent ot the movement ot said una a slide-rod pivotall)Y car- Vrot-rest trame, and a slidef, by saai toe-board trame and 'ri .n c'ed to slide on, said. slide-rodv` means on said slide-rod to retain said slide-bracl-et in position to hold th:` toe-hoard frame inclined toward said seat and springs to rieldingly hold raid slide-rod in position to retain said toe-board Ytrame inclined trom said seat.

pivetalljx supnorted thereon and arranged to toot-luralw'l b adjusted torfiud and trom the chair seat, a toe-board 'traine piroted to swing,- on said 'toot-hoard trame toward and from said .seat and haring' lerers extending` below said toeboard trame. a slide-rod pivot-ally mounted on said 'trait-hoard trame and arranged for longitudinal more/nient with respect thereto` springs tending to torce said slide-rod tornai-d, a slide-bracket carried by .said le 'ers and arranged to slide on said slide-rod and to engage notch thereon to retain said toe-board 'fi are inclined toward said seat, and arranged to engage means on said slidered to sustain said toe-board inclined from .said sea' in opposition to the tension ot said springs, which may Yield to permitthe loinritudinal movement oit said slide-rod -and permit said toe-board trame to assume a iur-sition beyond its normal yieldinglj.rv sustained position,

1lln a dent: i chair, the combination with a seat siniporting trame, ot a :toot-rest frame pirotall;v supported thereon and arranged to be adjusted toward and from the chair seat, a toe-board trame pivoted to said toot-rest 'tram-e and ari-aimed to be inclined either ton'ard or trom said seat, and having levers extending; rearwardly, a slide-bearing mounted to rock on said toot-rest trame, a slide-rod haring` a notch` mounted tor longitudinal morement in said slide-bearing, means on said slide-rod arranged to limit its 't'orn'ard movement in said bearing, a )fol-te on said slide-rod, springs connecting said yoke With said 'toot-board Atrame and tending to torce said slide-rod forward, an abut'- ment on said slide-rod, and a slide-bracket; carried by said levers and normally held by said abutment in position to yieldingrly tain the toe-board frame inclined trom said seat, and arranged to engage said notch to rigidly retain said toe-board trame inclined toward said seat.

5. In a dental chair, the combination with a seatsupporting` trame, ot a toot-rest trame pirotall;Y mounted thereon and arranged to he adjusted toward and from the chair seat, a toc-hoard trame piroted to said toot-l'ioard traine and arranged to be inclined with respect to said Ytoot-l'ioard trame either to Y'ard or trom the chair seat and having levers extended belov.Y said footrest trame, a slide-liiearingiA mounted to roel: on said toot-rest trame a slide-rod mounted tor longitudinal movement in said slidebearing'. ineans arranged to limit the movement et said slide-rod, yielding means tending` to 'torce said slide-rod tornar-d, an abutment on said slide-rod`t a slide-hrzufhet; carried by said levers and norn'iall)v held by said abutment in position to rielitiinjl);Y sustain the toe-board inclined troia said seat. and arranged to engage said notch to rigidljv retain said toe-board trame inclined toward said seat.

G. ln a dental chair, the c unbination with a seat suppertingl'rame4` o t a toot-rest Ytrame pirotallyv supported thereon and arranged to be adjusted toward and trom the chair seat, a toe-board trame piroted to said toot;- board 'trame and arranged to be inclined with respect thereto either toward or Vtroni said seat. a slide-l :aring mounted to rock on said toot-rest traine.y a slide-rod mounted tor longitudinal movement in said slide-bearing, means arranged to limitA the morenxent ot said slide-rodv` a shaft mounted to rock on said toe-board trame and carrying;r a slidebracket arranged to slide on said slide-rod` an abutment tor said slide-bracket arranged to yieldingh7 sustain said toe-board trame inclined from said seat, a notch on said slide-rod arranged to rigidlyv retain said slide-bracket in position to retain said toeboard 'trame inclined toward said seat, and a pedal on said rock-shaft whereby said shaft ma \T be rocked to release said slidebracket from said notch and mored to etl'cct the afljnstn'ient ot said toe-board traine with. respect to said seat.

In a dental chair. the combination with a seat suporting trame. et a toot-rest trame pivotally supported thereon and arranged to be adjusted toward and troni the chair scat. a toe-board trame pivoted to said toot-rest trame and arranged to be inclined with respect to sai-d foot-board trame either toward or from said seat, a slide-rod carried by said 'toot-rest trame, means on said toc-board 'frame cool eratire n'ith said slide-rod to ,rigidlyretain the toe-board frame inclined toward the chair seat and yieldingly sustained inclined away from said seat, and means whereby said foot-rest frame may closely-approach the floor, comprising compensating and compounding links and levers arranged to adjust said 4foot-rest frame towardand vfrom said seat.

8..In.a dental chair, the combination with al Aseat .supporting iframe, of .a foot-rest ramepivotally supported thereon and arranged to be .adjusted toward and from the vchair seat, a toe-board frame pivoted to said `toot-rest frame and arranged to be inclined either toward or from said seat, a slide-rod carrie-d by said foot-rest'fiame, and means on said toe-board frame cooperative with said. slide-rod to retain said toe-board frame inclined toward .the chair seat, and yieldingly .sustain ,it inclined away from said seat, locking mechanism automatically actuated f' to support .said :foot-rest iframe in any adj-usted rposition within its range of movement, .and means comprising. compensating and compounding link and lever mecha- .nismarranged to release said lock and eiiect -tlfie adjustment of said foot-rest Jframe.

-9. In :a ldental chair, the combination with --a seatsupporting frame, having depending iramebrackets, of .a foot-rest frame pivot- -ed to said .brackets and arranged to move ltoward Kand from the chairr seat without tiltautomatically :actuated locking means of saidoot-rest'trame.

10.111 a .dental chair, 'the combination with a supporting base, of a seat supporting i-.raine having,- frame brackets, levers pivotallymounted on said brackets, a oot-rest :trame .pivotally connected with said levers, y links '-rigidly `.joined transversely, p ivotally connected-with saidbrackets land with said toot-rest drame, .the pivotal axes oi said 'levers andlinks Ypassing through the *four angles oi ^.a Ixpatalle-legi"am whereby movement of said ilinks .effects .the adjustment of said foot-rest obliquelyftoward .or `from ythe cha-ir seat, maintaining the .toot-rest in a definite anulararelationito .the :axis of said base.

.lilfllln :a dental chair, the combination wit-lia supporting ibase, of a 'seat supporting .traine .having depending frame brackets, .le-

vers pivoted to rock on said frame-brackets,

l a toot-rest frame .pivotally mounted on said leversVlinks pivotally connected with said frame-brackets and Ltr-amedisposed;in Aparallel relation with said with said foot-rest levers whereby .the iinovement-of said `-footlrestunaybe .effected toward .and from said Vseat without ,changing lits angular 'relation to the axis of said base, and .locking means carried by said levers arranged to automatically support Said foot-rest in any adjusted position within its range of movement, and means operative to contemporaneously release said locking mean-sand eliect the adjustment of said foot-rest iframe.

12. ln a dental chair, the combination with a seat supporting frame, of levers forming rocker-arms mounted to rock on said iframe, a. -:toot-rest frame carried by said rocker-arms arranged to swing -tliereontoward androni the chair seat in the natur-al direction of the leg of a patientint-hechair, means arranged to maintain the yfoot-rest iframe substantially xhorizontal in any adjusted position, and compounding means arranged to eiect the adjustment of said vfootrest frame, Acomprising a pedal lever and a link operatively connecting said pedalflevei' patient in the chair,'meansconnectingl said `frames .arranged'to maintain the 'toot-rest fra-me substantially horizontal in any adjusted position, vmeans for locking saidy foot-.rest 'frame in its adjusted position, comprising a v'looking-bar oscillatabily carried `byy said levers and having automatically actuated gripping means,- a 4locking-rod cooperative with) said gripping means a-rf ranged to retain saidy foot-rest frame in any adjusted position within its range of move- .inent, and :means .arrangedto etectl'the adjustinent of said foot-rest fra-me.

,14. In a dental chair, the combination with .a seat supporting 4vframe, oflevers mounted to rock on lsaid iframe, -a afoot-rest `:trame carried *by .said levers arranged vto .swing thereon toward and :from ,the chair seat, Ameans lconnecting saidl lframes arranged ',to maintain the toot-'rest frame substantial- 'ly horizontal in any adj-ustedipositionneans for locking said i'oot-rest-rame in litsadjustedjposition, comprising -a locking-bar -oscillatably :carried by said levers-and having Aautomatically .actuated Agripping means, a

'locking-.rod cooperative with saidMgri-pping means arranged to lretain said -foot-rest frame in any adjusted--position within vits range of movement, a pedallever-pivotedto said seat fsupporting"frame, and -a @link fop- Veratively connecting `said lpedal lever -with said rocker-arms.

`l`5ln a dental chair, the combination with ,a seat supporting `frame, of il'evers mounted 'to rockfon -said frame, afoot-rest 'frame carried :by said llevers arrangedito swing thereon-toward and lfromlthe ichair seat, 4means 4connecting said frames arranged to maintain the toot-rest frame substantially horizontal in any adjusted position, means tor locking said foot-rest trame, comprising a locking-bar oscillatably carried by said levers and having a lugY provided With an aperture, a locking-rod iivotally connected with said seat supporting frame andetending through said aperture, means tending to rock said locking-bar in position to bite said locking-rod and thereby ret-ain said-foot-rest frame in any adjusted position Within its range of movement, and pedal mechanism connected to eiect thc adjustment oil'I said foot-rest frame and having means to rock said ilocking-bar and thereby release its bite on said locking-rod.

IG. In a dental chair, the combination with a seat supporting frame, of levers -forming rocker-arms mounted to rock on said iframe, a foot-rest frame carried by said rocker-arms arranged to swing thereon toivard and from the chair seat, means connecting said Yframes arranged to maintain the foot-rest trame substantiallyT horizontal, a locking-bar oseillatably carried by said levers, a locking-rod connected With said seat supporting trame cooperative with said locking-bar to retain said Jroot-rest trame in any adjusted position vvithin its range of movement` means tending to cause said hacking-bar to bite said locking-rod, a pedal lever pivoted to said seat supporting frame, a link connecting said pedal lever with said rocker-arms, a pedal mounted to rock on said pedal lever, links connecting said pedal with said locking-bar to eli'ect the oscillation thereof and thereby contemporaneously release its bite on said locking-rod ivhen said Atoot-rest frame is adjusted by-the movement of said pedal.

lT. In a dental chair, the combination with a seat supporting frame, or' levers mounted to rock thereon, a -toot-rest trame pivotally carried by said levers and arranged to be swung thereby tovfard and from chair seat, means Vfor retaining said toot-rest trame in any adjusted position Within Yrange of movement, a locking-bar carried by said lever" and having an aperture therein. a locking-rod pivoted to said s at supporting-fl2 ame Vand extending through said aperture, a shoe disposed in said aperture and arranged to bear against said lockingrod. means tending to cause said locking-bar to bite said locking-rod, a pedal lever pivoted to said seat supporting trame, a link Connecting said pedal lever, and means connecting said pedal with said locking-bar whereby the movement of said pedal with respect to the pedal lever eti'eets an oscillatory movement or' said locking-bar to release its bite on said locking-rod and permit the adjustment offsaid root-rest frame tovvard and from the chair seat.

1S. In a dental chair, the combination with a seat supporting frame, of levers 'forming rocker-arms mounted to rock ou s. d Yfiume, a foot-rest Carried by said rockerarms and arranged to be adjusted toward and 'from the chair seat, a locking-bar pivflly carried by said rocker-arn'is and havi g an aperture therein, a locking-rod pivoted to said seat supporting frame and extendine through said aperture, yielding means tending to cause said locking-bar to bite said locking-rod, a pedal lever pivoted to said seat iframe, a link connecting said pedal lever ivith said locking-bar, a pedal pivotally mounted on said lever, a rocker member carried by said pedal lever, a link connecting said pedal with said rocker member,V a link Vcon ecting said rocker member vfith said locking-har whereby the rocking movement or said pedal on the pedal lever eileets an oscillatory movement ot said lock- -bar in opposition to said yielding means` to release its bite on said locking-rod and permit the tree adjustment ot the foot-resi.

l). In a dental chair, the combination with a seat supporting trame, ot levers Vforming roel-:er arms mounted to rock on said lrame, a toot-rest `lrame pivolallv carried by .said rocker-arms, arranged to swing thereon toward or trom the chair seat, locking means urrai ged to support said toot-rest Ytraine in any adjusted position within its range ot movement, comprising an oscillatory member carried by said levers, having*r an aperture therein` a locking-rod carried by said seat :trame and extending through said aperture, a spring lending to rock said e king member to bite said locking-rod and t ereby support said toot-rest 'trame in any adjusted positionavithin its range ot movement, a pedal lever pivoted to swing on said .seat iframe, a link connecting said pedal lever 1th said rocker-arms. a pedal pivotnounted on said pedal lever, a hellcrr-.nli-lever carried by said pedal leverI` a link connecting said pedal vithsaid bellcrank-lever, and a link connecting said bellcrank-lever with said locking member whereby the rocking of sai-d pedal on said pedal lever etiects an oscillatory movement or' said locking member in opposition to said spring to release its bite Afrom said lockf-rod and permit the Ytree adjustment o1" the 'toot-rest by said pedal.

0. in a dental chair, the eon'ibination with a seat supporting frame, of levers Yform-V yielding' means tending to cause saidlocking means to bite the smooth surface of said lockii'ig-rd. y j ,L

l the j combination wi'tl-r a yseatsupport igrraine, of a foo't-r'est frame pii'io'tally nioinited to swing toward and from the chair seat, locking means arranged to support said foot-rest frame in different adjusted positions with respect to said chair seat, comprising a locking-rod, a locking member having an aperture therein through which said locking-rod extends and provides a gripping pad arranged to engage said locking-rod, and a shoe arranged to bear against said locking-rod to effect the jamming of said gripping pad against said locking-rod, and yielding means tending to rock said locking means to cause the gripping pad to bite said locking-rod.

22. In -a dental chair, the combination with a seat supporting frame, of a foot-rest frame pivotally mounted to swing toward and from the chair seat, means for supporting said foot-rest frame in any adjusted position within its range of movement, comprising a locking-rod carried by said seat supporting frame, a locking member oscillatably mounted to bite said locking-rod and having a gripping pad, a shoe adjustable therein, ar 'anged to bear against said locking-rod, and a spring tending to turn said locking member to effect a jamming of said rod between said shoe and said gripping pad.

23. In a ldental chair, the combination with a seat supporting frame, of a foot-rest frame arranged to swing thereon toward and from the chair seat, means connected to retain said foot-rest frame in any adjusted position within its range of movement, comprising a locking-rod carried by said seat supporting frame, a locking member cooperative to bite said locking-rod and having a gripping pad arranged to bear against said locking-rod, a shoe arranged to engage said locking-rod in opposition to said gripping pad, means pivotally supporting said shoe, being adjustable toward and away from said locking-rod, means tending to rock said locking member to jam said locking-rod between said shoe and said gripping` pad, and means acting in opposition to said yielding means, arranged to rock said locking member to release said locking-rod and contemporaneously effect the adjustment of said foot-rest frame toward or from the chair seat.

24. In a dental chair, the combination with a seat supporting frame, levers pivotally carried by said frame, a foot-rest frame pivotally mounted on said levers, links pivotally connecting the seat frame with said foot-rest frame, and buffer springs carried by said links arranged to limit the movement of said foot-rest frame in either direction toward or from the chair seat.

and tending 25. dental chair provided with a seat supporting fran'ie, a foot-rest frame pivoted to said 'seat supporting frame and 'arranged to be :adjusted toward and from vthe chair seatfand yielding means servingas a buffer to force said foot-rest fame away from said seat.

26. A dental chair provided with a seat supporting frame, a foot-rest frame pivoted thereon and arranged to move toward and from the chair seat, and a spring active when said foot-rest closely approaches said seat, serving as a buffer and tending to force said foot-rest away from said seat.

27. A dental chair provided with a seat supporting frame, levers pivoted to said frame, and pivotally supporting a foot-rest frame, links pivoted to said seat supporting frame and to said foot-rest frame, and buffer springs carried by said links arranged to engage the foot-rest frame and limit its lower-most position, and to engage said chair frame to limit the upper-most movement of said foot-rest frame.

28. A dental chair provided with a seat supporting frame and having a foot-rest frame pivoted thereon, a toe-board frame pivoted on said foot-rest frame and arranged to be inclined either toward or from the chair seat, a slide-rod carried by said footrest frame and arranged to move longitudinally with respect thereto, springs tending to force said slide-rod forwardly, a slidebracket carried by said toe-board frame and arranged to slide on said slide-rod, a collar on said slide-rod, a buffer spring between said collar and said slide-bracket, and means including a resilient buffer arranged to limit the longitudinal movement of said slide-rod.

29. A. dental chair having a foot-rest frame and provided with a toe-board frame pivoted to swing thereon, and be inclined either rearwardly or forwardly with respect thereto, a pivoted slide-bearing carried by said foot-rest frame, a slide-rod mounted to slide longitudinally in said bearing and to swing with respectto said foot-rest frame, means including a resilient buer arranged to limit the outward movement of said slide-rod, yielding means tending to force said sliderod forwardly, a slide-bracket carried by said toe-board frame and arranged to slide on said slide-rod, and means including a resilient buffer, against which said slidebracket bears, to sustain said toe-board outwardly inclined.

30. A` dental chair having a foot-rest frame, a toe-board frame pivoted thereon and arranged to be retained inclined rearwardly with respect to said foot-board frame, normally sustained inclined forwardly with respect thereto, or forced outwardly from said normal outwardly inclined position, a slide-bearing pivotally carried by said footrest frame, a slide-rod mounted for longitudinal movement in Said bearingr and having a notch therein, a slide-bracht Czrried by said toe-boarril 'frame and arranged to slide on stlide-rod and be engaged by Said notch7 Welding` abutments arranged to limit the normal movement of said slide-bracket on said slide-rod, and yielding means tending to torce said slide-rod forwardly, and arranged to yield to permit Said toe-board .trame to be fori-ed ontxmrdl;v beyond its normal ont\'\.'ardly Sustained position.

In witness whereof, I have hereunto sot my hand this 13th day of April, A. D. 1922.

GEORGE D. HECK. 

